‘Perfect Storm’ Increases Risk of Atypical Myopathy

The British Equine Veterinary Association (BEVA) have warned of a heightened risk of atypical myopathy in grazing horses.

BEVA issued the warning, describing the hot summer as creating potential hay shortages and the forecast of early transatlantic storms as creating the ‘perfect storm’ for the disease.

Atypical myopathy is a muscle disease caused by the toxin hypoglyxin A. The toxin was not identified as the root cause of the disease until 2013, despite the disease being reported in horses since the 1960s.

In the UK, the most common source of hypoglyxin A is Sycamore tree seeds. The helicopter shape seeds have been reported to travel up to 4km, with the high winds increasing there fall rate and chance of ingestion dramatically.

Although horses do not choose to eat sycamore seeds, BEVA member Adam Redpath warned that bare pastures result in a “greater tendency for them to be ingested, as horses are foraging for every last blade of grass”.

A toxic dose for a horse can range from under 100 to several thousand seeds. Seeds can also contaminate water courses, especially if they are damaged by trampling feet.

Horses with atypical myopathy may become weak or reluctant to move and usually develop severe colic-like symptoms as a result of muscle breakdown. Horses may also pass dark-coloured urine.

In regard to their warning, BEVA has urged horse owners to take the necessary steps to prevent the disease.

BEVA Recommend

• Identifying trees.
• Collect seeds or exclude horses from affected areas.
• Feeding supplementary hay to prevent excessive foraging.
• Monitoring horses carefully for signs and symptoms of the disease.

Redpath also advised;

Early veterinary intervention is essential to achieve a favourable outcome.”

“You should contact your vet immediately if you spot any of the signs. Check your fields for sycamore seeds as this will help your vet to make a rapid diagnosis. Specific blood tests have been developed to both measure exposure to the toxin and to make a diagnosis, thanks to research funding from The Horse Trust.”